Makefile.in: set dev-install target during ./configuration

Rather than relying on the sourced environment variables, create
Makefile with the correct dev-install target folder during the
./configure run. Slightly prettified the file.

Makefile.in

-# just dumb wrapper; make install comes later
+# @configure_input@
+# FIXME: create 'install' and 'check' target
 
 SHELL=/bin/sh
 
 all:
 	@. ./*[Ee]nv.[Ss]et.sh && \
-	./bootstrap && \
-		cd instsetoo_native && ../solenv/bin/build.pl -P@BUILD_NCPUS@ --all -P@BUILD_MAX_JOBS@
+        ./bootstrap && \
+        cd instsetoo_native && \
+        ../solenv/bin/build.pl -P@BUILD_NCPUS@ --all -P@BUILD_MAX_JOBS@
 
 distclean:
 	@. ./*[Ee]nv.[Ss]et.sh && \
-	dmake distclean
+        dmake distclean
 
 clean:
 	@. ./*[Ee]nv.[Ss]et.sh && \
-	dmake clean
+        dmake clean
 
 dev-install:
 	@. ./*[Ee]nv.[Ss]et.sh && \
-		ooinstall -l $$SRC_ROOT/install && \
-		echo && \
-		echo "Developer installation finished, you can find it here:" && \
-		echo "$$SRC_ROOT/install"
+        ooinstall -l @abs_builddir@/install && \
+        echo "" && \
+        echo "Developer installation finished, you can now execute:" && \
+        echo "@abs_builddir@/install/program/soffice"